DIN 2691 Silicone Gasket
Manufacturer & Custom Solutions
Gaskets for Tongue and Groove Flanges
DIN 2691 covers gaskets for tongue and groove flanges, PN10 to PN160. Many old machines and plants in Europe still use this type of flange. Gaskets for these flanges are usually made from compressed fiber, PTFE or graphite, and metal gaskets for high pressure lines. Silicone is a better choice for repair work when you need a soft gasket that fills the groove well and works from -60°C to +200°C. Food grade material is also available. ZSR supplies silicone gaskets made to DIN 2691 dimensions. Send us the DN number or an old gasket sample, and we will make the right part for you, even in small quantity.
FDA 21 CFR 177.2600
Rubber Articles Intended for Repeated Use
LFGB 30&31
EU Food Contact Materials
USP Class VI / ISO 10993
Biocompatibility of Medical Devices
RoHS / REACH
Environmental Compliance
UL 94
Flammability of Plastic Materials
Built to Your Exact Spec
Custom Silicone Gaskets Options
| Image | Product | Type | Short Info | Action |
|---|---|---|---|---|
 | DIN 32676 Silicone Gasket | Standard & Size | DIN 32676 tri-clamp silicone gaskets, FDA food grade, full size range in stock at ZSR factory. | View Details |
 | AS568 Standard Silicone Gaskets | Standard & Size | AS568 standard-size silicone gaskets for groove-based sealing applications. | View Details |
 | DIN 3869 Silicone Sealing Ring | Standard & Size | DIN 3869 profile sealing rings in silicone for hydraulic ports, working from -60°C to +200°C. | View Details |
 | EN 1514-1 Silicone Gasket | Standard & Size | EN 1514-1 silicone flat gaskets for PN flanges, IBC and FF types, standard and custom sizes. | View Details |
 | Custom Die Cut Silicone Gaskets | Standard & Size | Flat silicone gaskets cut to any shape from sheet stock. Precision cutting for exact fits. | View Details |
 | ISO 7483 Silicone Gasket | Standard & Size | Silicone gaskets to ISO 7483 for ISO 7005 flanges, made for international projects and tenders. | View Details |
 | Custom Molded Silicone Gaskets | Standard & Size | Three-dimensional silicone gaskets made by compression or injection molding. For complex sealing shapes. | View Details |
 | ISO 1127 Silicone Gasket | Standard & Size | Sanitary silicone gaskets matched to ISO 1127 stainless steel tube sizes for food and pharma lines. | View Details |
 | Standard Flange Silicone Gaskets | Standard & Size | Silicone gaskets cut to fit pipe flanges. Matches ANSI, DIN and JIS bolt patterns. | View Details |
 | B16.21 Silicone Gasket | Standard & Size | ZSR makes silicone gaskets to ASME B16.21, ring type and full face type, for Class 150 to 2500 pipe flanges. | View Details |
 | ISO 2852 Silicone Gasket | Standard & Size | ISO 2852 silicone clamp gaskets for food industry couplings, FDA grade, factory direct from ZSR. | View Details |
 | Tri-Clamp / Sanitary Silicone Gaskets | Standard & Size | Hygienic silicone gaskets for food and pharmaceutical pipe connections. CIP and SIP compatible. | View Details |
 | B16.5 Silicone Gasket | Standard & Size | Silicone gaskets from ZSR sized to fit ASME B16.5 flanges, NPS 1/2 to 24 inch, Class 150 to 2500. | View Details |
 | Metric Size Silicone Gaskets | Standard & Size | Metric dimension silicone gaskets for international equipment standards. | View Details |
 | DIN 7603 Silicone Sealing Ring | Standard & Size | Flat silicone sealing rings made to DIN 7603 for screw plugs, banjo bolts and threaded fittings. | View Details |
 | DIN 2690 Silicone Gasket | Standard & Size | Silicone flat gaskets to DIN 2690 / EN 1514-1 dimensions for PN6 to PN40 flanges, food grade available. | View Details |
 | DIN 2691 Silicone Gasket | Standard & Size | Silicone gaskets made to DIN 2691 for tongue and groove flanges PN10 to PN160, ideal for plant repair. | View Details |
 | DIN 11851 Silicone Gasket | Standard & Size | Food grade silicone gaskets for DIN 11851 sanitary unions, DN10 to DN150, FDA material. | View Details |
 | FDA Food Grade Silicone Gasket | Grade | Food-safe silicone gaskets for processing equipment. FDA-compliant and taste-neutral. | View Details |
 | Medical Grade Silicone Gasket | Grade | Biocompatible silicone gaskets for medical devices. Sterilizable with full documentation. | View Details |
 | Industrial Grade Silicone Gasket | Grade | General-purpose silicone gaskets for industrial sealing. Reliable, durable and cost-effective. | View Details |
 | High Temperature / Heat Resistant Silicone Gaskets | Special Function | Heat-resistant silicone gaskets rated for continuous use above 200°C. For ovens and furnaces. | View Details |
 | Flame Retardant Silicone Gaskets | Special Function | Self-extinguishing silicone gaskets meeting UL 94 V-0. For fire-safety applications. | View Details |
 | Solid Silicone Rubber Gaskets | Materials | Solid silicone rubber gaskets with excellent compression set resistance and long service life. | View Details |
 | Fluorosilicone (FVMQ) Gaskets | Materials | Fuel and solvent-resistant silicone gaskets for chemical processing and automotive applications. | View Details |
 | Transparent / Clear Silicone Gaskets | Color | Clear silicone gaskets for visible sealing and light-transmitting applications. | View Details |
 | Black / White Silicone Gaskets | Color | Standard black and white silicone gaskets. Fastest delivery from stock. | View Details |
What Are Tongue and Groove Flanges?
Tongue and groove is a clever flange design built around one idea: trap the gasket so it can never escape. One flange face carries a raised ring — the tongue. The mating flange carries a matching channel — the groove. The gasket sits down inside the groove, and when the flanges close, the tongue enters the groove and locks everything in place.
This design gives the gasket three big advantages:
Self-centering
the gasket drops into the groove and sits perfectly centered, every time. No alignment skill needed.
Blowout-proof
the groove walls hold the gasket on all sides. Internal pressure cannot push it out, which is why this facing is used on higher pressure lines.
Protected sealing
the gasket is shielded inside the joint, away from weather, handling damage, and flow erosion.
DIN 2691 is the standard that fixes the gasket dimensions for this flange type — matching the tongue-and-groove faces defined by DIN 2512, for PN10 to PN160. When your drawing says DIN 2691, we know exactly what size ring your groove needs.
DIN 2691 Dimensions and Tolerances
In a tongue and groove joint, the gasket ring is fully confined — so its dimensions must be right in every direction. Common sizes (mm):
DN | Gasket ID (d1) | Gasket OD (d2) | Ring Width | Recommended Thickness |
|---|---|---|---|---|
DN15 | 29 | 39 | 5 mm | 2 mm |
DN25 | 43 | 57 | 7 mm | 2 mm |
DN40 | 61 | 75 | 7 mm | 2 mm |
DN50 | 73 | 87 | 7 mm | 2 mm |
DN65 | 95 | 109 | 7 mm | 2 mm |
DN80 | 106 | 120 | 7 mm | 2 mm |
DN100 | 129 | 149 | 10 mm | 2.5 mm |
DN125 | 155 | 175 | 10 mm | 2.5 mm |
DN150 | 183 | 203 | 10 mm | 2.5 mm |
DN200 | 239 | 259 | 10 mm | 2.5 mm |
DN250 | 292 | 312 | 10 mm | 2.5 mm |
DN300 | 343 | 363 | 10 mm | 3 mm |
The groove itself is defined by DIN 2512 — typically about 4.5 mm deep, with the tongue standing slightly less.
Why thickness is critical here
In this design, the flanges close metal-to-metal, and the gasket compresses inside the groove. Too thin — the gasket never fills the groove, and the joint leaks. Too thick — the flanges cannot close fully, the tongue bottoms out, and the bolt load goes into the gasket instead of the flange faces. The right thickness leaves the groove just filled, with the seal under firm, controlled compression.
How ZSR guarantees the fit
For new sizes we mold sample gaskets and test-close them in reference flanges, checking closure, compression, and ID/OD fit before production. Your gasket arrives already proven against the groove it will live in.
Material and Profile Recommendations
The confined groove changes the material rules:
Tell us your medium, temperature, and flange class — we will confirm the right material before you order, free of charge.
What Is DIN 2691?
DIN 2691 is a German standard that defines the dimensions of gaskets for tongue and groove pipe flanges — the flange facing where a raised tongue on one flange locks into a matching groove on the other, with the gasket trapped inside. Published by DIN, the German Institute for Standardization, it covers sizes from DN10 to DN1000 and pressure ratings from PN10 to PN160. The current tables date from the classic 1971 edition — and they are still working hard today, because countless European plants built decades ago still run these flanges and still need replacement gaskets made to this exact standard.
Key Points of the Standard
At ZSR Silicone Parts, we supply silicone gaskets to DIN 2691 dimensions for plant maintenance and repair — even in small quantities, even from just an old sample. Send us your DN number or your worn gasket, and we will quote within 24 hours.